Circlips

Abstract

A circlip ( 8 ) comprises a band of material forming an incomplete ring, and has curved bearing surfaces ( 10, 11 ) at opposite ends of the major transverse dimension of the band. The major transverse dimension is generally oriented at less than 90°, and preferably a small acute angle α, to the central axis A of the ring in the unstressed state of the circlip ( 8 ).

What is claimed is:  
     
       1. A circlip comprising a band of material in part-conical form forming an incomplete ring, said band having a transverse major dimension along a major axis and having a central axis, and having bearing surfaces located at opposite ends of said dimension of the band, said bearing surfaces curved in transverse cross-section wherein said dimension is at an angle of less than about 45° with respect to the central axis when in an unstressed state of the circlip. 
     
     
       2. A circlip as claimed in claim  1  wherein the curved bearing surfaces are convex. 
     
     
       3. A circlip as claimed in claim  1  wherein the bearing surfaces are part-circular in transverse cross-section. 
     
     
       4. A circlip as claimed in claim  1  wherein the bearing surfaces have substantially the same radius of curvature. 
     
     
       5. A circlip as claimed in claim  1  wherein the bearing surfaces are substantially continuous around a circumferential extent of the circlip. 
     
     
       6. A circlip as claimed in claim  1  wherein the said major dimension is at an angle of less than about 15° to the central axis. 
     
     
       7. A circlip as claimed in claim  1  wherein the transverse band cross-section has substantially straight, parallel major sides and is substantially symmetrical about the major axis thereof. 
     
     
       8. A circlip as claimed in claim  1  wherein the band has vent apertures therein. 
     
     
       9. Apparatus for connecting first and second members, the apparatus comprising: 
       a male portion of the first member;  
       a female portion of the second member for reception of the male portion of the first member; and  
       a circlip comprising a band of material in part-conical form forming an incomplete ring, said band having a transverse major dimension along a major axis and having a central axis, and having bearing surfaces located at opposite ends of said dimension of the band, said bearing surfaces curved in transverse cross-section. wherein said dimension is at an anole of less than 90° with respect to the central axis when in an unstressed state of the circlip;  
       wherein the male and female portions have respective annular regions for abutting the bearing surfaces at opposite ends of the major transverse dimension of the circlip, whereby, in use, the circlip inhibits relative axial displacement of said portions tending to compress the circlip.  
     
     
       10. Apparatus as claimed in claim  9 , wherein the annular regions are annular recesses for receiving the respective bearing surfaces of the circlip. 
     
     
       11. Apparatus as claimed in claim  9  wherein at least one of the male and female portions has an abutment surface adjacent the annular region for inhibiting dislocation of the bearing surfaces of the circlip from the annular region. 
     
     
       12. Apparatus as claimed in claim  9  wherein the annular regions are curved in transverse cross-section. 
     
     
       13. Apparatus as claimed in claim  12  wherein the annular regions are part-circular in transverse cross-section. 
     
     
       14. Apparatus as claimed in claim  13  wherein the radius of curvature of each annular region is substantially equal to a radius of curvature of the corresponding bearing surface. 
     
     
       15. Apparatus as claimed in claim  14  wherein, in transverse cross-section, the angle subtended by the ends of the curved surface of each annular region is greater than the angle subtended by the ends of the corresponding bearing surface. 
     
     
       16. Apparatus as claimed in claim  9  wherein the angle of said major dimension to the central axis of the circlip in the unstressed state is greater than the corresponding angle when the apparatus is assembled with the bearing surfaces of the circlip abutting the annular regions of the male and female portions, whereby the circlip is biased into engagement with the male and female portions in the assembled state. 
     
     
       17. Apparatus as claimed in claim  9  including resilient means located between the male and female portions for inhibiting relative axial displacement of the male and female portions in the opposite direction to the relative displacement inhibited by the circlip. 
     
     
       18. Apparatus as claimed in claim  9  wherein the first and second members are components of a Stirling engine. 
     
     
       19. Apparatus as claimed in claim  18  wherein the second member comprises an engine cylinder of said Stirling engine, the female portion comprising a cylinder mouth, and wherein the first member comprises a cylinder head, and the male portion comprising a base flange of the cylinder head. 
     
     
       20. Apparatus for connecting first and second members, the apparatus comprising: 
       a male portion of the first member;  
       a female portion of the second member for reception of the male portion of the first member; and  
       a circlip comprising a band of material forming an incomplete ring, and having, at opposite ends of a major transverse dimension of the band, bearing surfaces which are curved in transverse cross-section, wherein said major transverse dimension is generally oriented at less than 90° to a central axis of the ring in an unstressed state;  
       wherein the male and female portions have respective annular regions for abutting the bearing surfaces at opposite ends of the major transverse dimension of the circlip, whereby, in use, the circlip inhibits relative axial displacement of said portions tending to compress the circlip, wherein the angle of said major transverse dimension to the central axis of the circlip in the unstressed state is greater than the corresponding angle when the apparatus is assembled with the bearing surfaces of the circlip abutting the annular regions of the male and female portions, whereby the circlip is biased into engagement with the male and female portions in the assembled state.  
     
     
       21. A circlip comprising a band of material in part-conical form forming an incomplete ring, said ring having two ends and a gap between said ends, said band having a transverse major dimension along a major axis and having a central axis, and having bearing surfaces located at opposite ends of said dimension of the band, said bearing surfaces curved in transverse cross-section, wherein said dimension is at an angle of less than 90° with respect to the central axis when in an unstressed state of the circlip.